The present invention is related to a double-face lighting electro luminescent device including two lighting sets and a back electrode layer co-used by the two lighting sets to emit light from double faces.
A conventional electro luminescent (EL) cell is mainly used as backlight cell, advertisement sign or decoration.
Referring to FIG. 3, a EL cell 8 is a thin sheet composed of a transparent substrate 81, a front electrode layer 82, a lighting layer 83, a back electrode layer 84 and an insulating packaging layer 85 which are sequentially overlaid on the transparent substrate 81. By means of applying AC voltage between the front and back electrode layers 82, 84, the lighting layer 83 emits light through the transparent substrate 81.
In the same lighting area, the above EL cell 8 can only emit light from one face to serve as backlight of liquid crystal display module 9. In the case that the EL cell is applied to a mobile phone with double panels, it is necessary to use two EL cells 8 in cooperation with two liquid crystal display modules 9 as shown in FIG. 4. Such measure is troublesome and time-consuming and leads to waste of material.
It is therefore a primary object of the present invention to provide a double-face lighting electro luminescent device in which two lighting sets are respectively overlaid on two opposite faces of the back electrode layer. The back electrode layer is co-used by the two lighting sets. Two front electrode layers and the back electrode layer independently control the lighting sets to respectively emit light. Accordingly, one single EL device can achieve double-face lighting effect.
It is a further object of the present invention to provide the above double-face lighting electro luminescent device in which one back electrode layer is co-used by two lighting sets. In addition, the transparent substrates of the two lighting sets achieve the insulating packaging effect. Therefore, the processing time is shortened and the material is saved.
According to the above objects, the double-face lighting electro luminescent device of the present invention includes a back electrode layer and two lighting sets overlapped with the back electrode layer. The back electrode layer has a first face and a second face opposite to the first face. The two lighting sets are respectively overlaid on the first and second faces. Each lighting set is composed of a lighting layer, a front electrode layer and a film-like transparent substrate which are sequentially overlaid on each of the first and second faces, whereby the two front electrode layers and the back electrode layer control the lighting layers of the lighting sets to emit light.
The present invention can be best understood through the following description and accompanying drawings wherein: